Straight-tube fluorescent lamps have been widely available as general illumination, and their luminous efficiency is as extremely high as 100 lm/W to 120 lm/W. In recent years, however, under the environmental regulations in Europe and others, for example, the RoHS regulations, there have been active movements for demanding new illumination lamps using no Hg. Typical candidates thereof include LED and OLED illuminations, but fluorescent lamps such as Xe lamps using no mercury have also been reviewed.